Interferometric Mirror Position Sensing with Corner Cube Reference
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Solution Overview
Problem
Traditional optical sensors for determining the position and orientation of fast-steering mirrors in optical systems face limitations such as limited dynamic range, non-linearities, and calibration challenges, especially when the reference position is lost or scale factor errors occur, leading to operational disruptions.
Innovation Solution
The implementation of interferometric sensors with internal means for quickly re-establishing mirror position sensor reference and scale factor error correction, using a combination of photonic integrated circuits, corner cube reflectors, and flat reflectors to provide accurate and redundant position and orientation measurements, and a computer and optical-electronic system to control and track the mirror's motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional optical sensors are used to determine mirror position and orientation, then the system structure is relatively simple, but the dynamic range is limited and non-linearities occur
Solution Approach 1:
The patent replaces traditional mechanical/optical position sensors with an interferometric sensing system that uses light interference patterns to measure mirror position and orientation. This substitution enables high dynamic range and linear measurement capabilities while maintaining system compactness through integrated photonic circuits.
Solution Approach 2:
The patent introduces corner cube reflectors and flat reflectors as intermediary elements in the interferometric measurement path. These intermediaries enable precise position and orientation measurement by creating reference beams and measurement beams that interfere to produce position-dependent intensity patterns, resolving the contradiction between accuracy and complexity.
2Measurement precision
If traditional optical sensors are used, then the device complexity is lower, but calibration challenges arise when reference position is lost
Solution Approach 1:
The interferometric system performs self-calibration by using the corner cube reflector to return the measurement beam to its original position. When the mirror returns to the reference position, the interference pattern automatically indicates the reference state, eliminating the need for external calibration equipment and procedures.
Solution Approach 2:
The patent establishes a reference position beforehand using the interferometric system's ability to detect when the mirror returns to a known position through the corner cube reflector. This preliminary establishment of reference enables subsequent measurements to be made without recurring calibration challenges.
3Reliability
If traditional sensors are used, then the system is easier to operate, but operational disruptions occur due to scale factor errors
Solution Approach 1:
The interferometric system provides continuous feedback on mirror position and orientation through intensity measurements of the interference pattern. This feedback enables real-time detection and correction of scale factor errors, maintaining operational continuity while the control system adjusts parameters to compensate for measurement deviations.
Solution Approach 2:
The patent uses parameter changes in the interferometric measurement system, specifically varying the intensity distribution across the detector array to extract both position and orientation information. This approach corrects scale factor errors by analyzing the spatial distribution of interference fringes rather than relying on single-point measurements.
4Measurement precision
If interferometric sensors with internal reference re-establishment are implemented, then position sensing accuracy and dynamic range improve, but device complexity increases
Solution Approach 1:
The patent merges the position sensor, orientation sensor, and reference management functions into a single interferometric measurement system. By combining these functions and using integrated photonic circuits, the system achieves high measurement precision while reducing the overall complexity that would result from separate sensor systems.
Solution Approach 2:
The interferometric system with corner cube reflector serves multiple functions simultaneously: it measures mirror position, measures mirror orientation, and provides automatic reference re-establishment. This multi-functionality resolves the contradiction by achieving high precision measurement without proportionally increasing system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances the dynamic range and linearity of position sensing, allows for rapid re-establishment of reference points, and corrects scale factor errors, reducing operational disruptions and improving the accuracy and reliability of mirror positioning and tracking.
Implementation Method 1
a corner cube reflector coupled to a second side of the plate and being configured to reflect a first beam to a position based on a position of the plate
Implementation Method 2
a flat reflector coupled to the second side of the plate and being configured to reflect a second beam to at an angle based on the position of the plate
Implementation Method 3
The implementation of interferometric sensors with internal means for quickly re-establishing mirror position sensor reference and scale factor error correction
Data Source
AI summary
An optical system can include a mirror that reflects incoming light to a sensor for detection. The position and/or orientation of the mirror can be controlled to reflect incoming light from different locations and/or directions. Position and/or orientation of the mirror may be tracked and/or detected by an optical position sensor. The position sensor can transmit a beam to a reflector on the mirror, and the reflected beam can be received by the position sensor. Characteristics of the reflected beam can be measured to determine the position and/or orientation of the mirror. For example, the beam can be used for interferometric and/or intensity measurements, which can then be correlated with a position and/or orientation of the mirror.